This invention relates primarily to the repair and maintenance of surfaces such as indoor or outdoor, hard recreational surfaces and, particularly, to the resurfacing of tennis courts, basketball courts and the like. In the past, acrylic resurfacing material typically employed for tennis courts has been applied manually and thereafter spread about by a number of individuals working with hand-held, squeegee-like spreaders, typically 30" in width. The resulting surface coating often varies in thickness and exhibits unsightly streaks resulting from the uneven application and multi-directional spreading techniques common in the prior art. The surface coating can range from thin to thick and, as a result, often shows noticeable deterioration even within one year after resurfacing.
The prior art method is also labor intensive, time consuming and therefore very costly. More importantly, quality result is not assured.
According to this invention, an improved apparatus and a process for resurfacing relatively hard and flat surfaces such as, but not limited to, recreational surfaces such as tennis courts, are presented herein which have several advantages over the prior art.
The present invention relates to a mobile, self-propelled device which can spread and smooth resurfacing material uniformly over an entire court surface in a single pass. This, of course, represents a fraction of the time required by conventional manual application techniques.
The present invention not only permits significantly more rapid resurfacing, but also provides a far superior uniformity of thickness throughout the resurfaced area.
In our earlier filed application, a resurfacing apparatus and process are disclosed which offer many advantages over conventional court resurfacing techniques. This invention constitutes an improvement over the earlier apparatus and process.
According to one exemplary embodiment of the invention, an elongated frame, preferably constructed in three separable but substantially axially aligned sections, is supported on a plurality of freely rotatable casters. The total width of the three-section frame may be varied as desired, but preferably exceeds the width of a regulation size tennis court. Other sizes may be achieved by shortening or lengthening any or all of the frame sections, and/or by removing altogether the separable side sections, depending on the size of the surface to be refinished. In the preferred embodiment, the center frame section approximately 20 feet wide, and each side or wing section is approximately 19 feet wide.
An internal combustion engine is utilized to drive the device. The engine is preferably mounted on the center section of the frame along with a centrifugal clutch, a forward-neutral-reverse transmission, and a roller drive train to a live drive axle mounting a pair of drive wheels. The ends of the live drive axle are supported for pivotal movement between an operative positive ground-engaging position, a neutral position, and an inoperative position in which both drive wheels are raised above the ground. To this end, a unique torsional shaft arrangement allows about 80% of the weight of the center section of the frame to be directed onto the drive wheels for increased traction in the operating position. Rotation of the torsional shaft to raise or lower the drive wheels is accomplished by a hand crank manually actuated by the machine operator.
The resurfacing apparatus of this invention may also be steered by actuating one or the other of two upstanding levers, located on either side of a driver's seat mounted substantially in the middle of the center section. Each lever is operatively connected to a respective drive wheel. By rotating, for example, the right lever, the right drive wheel is lifted clear of the ground, thereby losing its traction. The left drive wheel, however, maintains its positive ground engagement and produces full traction so as to pull the left end of the unit ahead of the right end. Thus, actuating the right or left steering lever produces a braking action on the right or left end, respectively, of the unit, thereby permitting the unit to be steered as desired. The above described torsional shaft also permits the steering levers to act independently of one another, and without negative impact on the mechanism employed to raise and lower the drive wheels between operative and inoperative positions.
It should be understood, however, that once the device is accurately aligned, motor started and drive wheels engaged, the operator need not remain seated on the device, but may walk along side it as it moves across the surface. Only if it becomes apparent that the device is beginning to move off course does the operator need to mount the unit and redirect the unit via the steering mechanism.
The two side frame sections which are substantially identical, are releasably attached to the center frame section for ease of transport and/or storage. The side sections are passive in the sense that they contain no portion of the drive train or steering systems of the unit.
Extending along front and rear faces of the unit are a plurality of channel members, each of which includes web and flange portions. Three such channel members are pivotally mounted to the three respective frame sections along both the front and rear faces of the unit. Thus, in one exemplary embodiment, a total of six such channel members are employed. The channel members along the front and rear of the machine, respectively, are in substantial axial alignment, and at the same time, are mounted substantially independently of each other such that all of the channel members are free to float relative to the frame sections to which they are attached.
Front and rear flanges of the channel members extending across the front face of the unit support leading squeegee-type blades and a trailing bristle brushes, respectively. Along the rear face of the machine, aligned channel members each mount leading and trailing bristle brushes.
As used herein, the term "leading" indicates that the so-described component contacts the resurfacing material ahead of the "trailing" component. Further, the channels which extend along the front of the machine, and their associated squeegee-type blades and brushes, will be referred to as the "lead" or "leading" applicator, while the channel members which extend across the rear face of the unit, and their respective bristle brushes will be referred to as the "rear" or "trailing" applicator.
The above described arrangement is such that the leading squeegee-type blade of the lead applicator contacts the resurfacing material first, and pushes the majority of the material ahead of the machine, but allowing a limited quantity to flow underneath the blade. The trailing bristle brush of the lead applicator serves to further thin out and smooth the resurfacing material.
The leading and trailing brushes of the trailing applicator serve to even further spread and thin out the resurfacing material and, significantly, they function to eliminate tracks formed in the wetted surface by the drive wheels and casters, and create a finished texture in the acrylic material.
It is a further feature of this invention to provide squeegee-type blades which serve to cover gaps which are present between adjacent channel sections of the leading applicator. In a like manner, additional brushes are provided along the lead brush of the rear applicator to cover similar gaps.
It is a further feature of the invention to provide end brushes which extend substantially perpendicularly forward of the squeegee-type blades of the lead applicator so as to confine the resurfacing material within well defined boundaries, i.e., in the direction of travel of the unit. This is particularly advantageous for two-tone tennis court refinishing operations where the "in-bound" color differs from the "out of bounds" color.
With regard to both the lead applicator and rear applicator, it is a further feature of the invention that each of the channel members may be rotated upwardly away from the ground, and latched in an inoperative position to further facilitate transport and/or storage of the device.
It is still another feature of this invention to provide at least one transport dolly, for facilitating transport of a frame center section, when separated from at least one of the frame side sections.
In another aspect, this invention relates to an improved process for resurfacing a tennis court or other recreational court surface which is marked by boundaries, typically in the form of painted lines. In the past, after an asphalt or "black-top" court has been resurfaced, it has been necessary to re-paint the boundaries which, of course, resulted in additional time and expense to complete the process. In accordance with this invention, a relatively simple process is provided which overcomes the disadvantages of conventional techniques. In the exemplary embodiment, the process of this invention may be carried out as follows:
(a) covering existing court boundaries with strips of material, preferably adhesive-type tape which will not remove the paint when it is pulled up after the resurfacing operation;
(b) positioning a resurfacing device as described above adjacent, but outside the boundaries of the court, and preferably parallel to one of the end line, or width boundaries;
(c) applying resurfacing material, preferably a sand-filled acrylic material of predetermined viscosity, in front of the device, preferably along its entire width;
(d) moving the device forwardly along at least and preferably beyond the entire length and width of the court, spreading out and smoothing the resurfacing material by the leading and trailing applicators; and
(e) removing the strips of tape to expose the original boundary lines.
In the event the original boundary lines are in need of re-painting, it is preferable that the re-painting be done first, followed by steps (a) through (e).
It will be appreciated that, in an alternative procedure, the machine may be positioned to travel in a direction transverse to the court length. This is particularly advantageous when resurfacing a number of adjacent courts, since all of the courts may be completely resurfaced in two passes of the machine. In other words, in one pass, one half of all of the courts (and areas adjacent the end lines on one side) may be resurfaced as the machine travels in one direction, and the other half of all of the courts (and areas adjacent the end lines on the other side) may be resurfaced as the machine returns in an opposite direction.
In addition, more than one coat may be applied as desired. In applying two coats, for example, a particularly attractive texture may be created by applying the second coat in a direction substantially perpendicular to the first. This procedure creates a striking "linen-like" texture to the court, created by the brushes on the trailing applicator.
Additional objects and advantages of the invention will become apparent upon reading the detailed description of the invention in conjunction with the accompanying drawings.